1. Field of the Invention
The present invention relates to a communication terminal that is widely employed for a navigation system mounted on a mobile unit.
2. Description of the Related Art
A car navigation system that is mounted on a vehicle that is a typical mobile unit displays a map on a display unit, based on a current location of the vehicle positioned, with a mark indicating the current location of the self vehicle superposed on its map.
In the car navigation system, a positioning unit for positioning the current location of the vehicle comprises a GPS (Global Positioning System) receiver and various self-contained navigation sensors for calculating the current location from the travel distance and the moving direction of the vehicle.
Also, the map information for displaying a map on the display unit, the relevant information associated with the map information and various kinds of functional services are provided from an information center located outside the vehicle, employing a communication unit mounted on the vehicle.